Kosmos 27 (Russian: Космос 27 meaning Cosmos 27), also known as Zond 3MV-1 No.3 was a space mission intended as a Venus impact probe.

The Blok L stage and probe reached Earth orbit successfully, but the attitude control system failed to operate.

[4] Kosmos 27 was launched at 03:24:43 GMT on 27 March 1964, atop a Molniya 8K78 s/n T15000-27 carrier rocket flying from Site 1/5 at the Baikonur Cosmodrome.

[2] The probe was the first dedicated 3MV spacecraft that the Soviets launched (earlier missions had been of the test "Object-Probe" versions as Kosmos 21).

The spacecraft successfully reached Earth orbit but failed to leave for Venus when the Blok L upper stage malfunctioned.